A variety of processes are available for the desulfurization of production exhaust gases, but their economic feasibility depends to a great extent on the concentration of the sulfur compounds. For example, the use of Claus apparatus for the production of sulfur from gases containing hydrogen sulfide is limited to a hydrogen sulfide concentration of at least 10% by volume. Furthermore, for reasons connected with the kinetics of the reaction, the gas must not contain any oxygen, and it must contain as little water vapor as possible. Furthermore, the Claus process can be used for the desulfurization of oxygen-free gases only with a certain amount of difficulty if the gases contain, in addition to hydrogen sulfide, organic compounds of sulfur, such as CS.sub.2, COS or mercaptans.
Gases which contain these compounds and are additionally characterized by an excess of oxygen and a high moisture content are, for example, the exhaust gases from the production of cellulose sulfate and viscose.
For the purification of the exhaust gases from the production of viscose it is known to adsorb the CS.sub.2 content of these gases onto active charcoal and then recover them by desorption. This process, however, is economical as a rule only when the CS.sub.2 concentration in the gas amounts to at least 2 g/m.sup.3 and the H.sub.2 S concentration is on the order of a few parts per million. In the case of CS.sub.2 concentrations of more than 2 g/m.sup.3 and H.sub.2 S concentrations of up to 3 g/m.sup.3, it is common to perform a combined recovery of carbon disulfide and elementary sulfur formed by the oxidation of the hydrogen sulfide on the active charcoal in the presence of oxygen. However, if the hydrogen sulfide concentration rises to more than 3 g/m.sup.3, the active charcoal is overheated on account of the high heat in the conversion of H.sub.2 S to elemental sulfur, and in conjunction with the CS.sub.2 there is a danger of fire.
It has therefore been necessary in these cases to remove the hydrogen sulfide by an oxidative preliminary washing with the use of, for example, an arsenite-arsenate washing solution, before passing the gas through the active charcoal to remove the carbon disulfide. This oxidative preliminary washing, however, had a negative effect on the economic feasibility of the exhaust gas desulfurization on account of the high investment cost and on account of the relatively great consumption of chemicals. In addition, waste water problems are created by the elimination of the irreversible by-products of the reaction.